The objectives of this proposed research are: (1) investigation of RNA-directed DNA polymerization and the coupled role of DNA polymerase and ribonuclease H activities using purified AMV DNA polymerase and model synthetic and natural RNA-RNA hybrids; (2) detection and characterization of additional enzymes and factors from virus particles and/or virus-infected cells involved in reverse transcription of AMV RNA; and (3) reconstitution of a viral RNA-directed DNA complex synthesizing viral DNA analogous to that found in the infected cell.